It's interesting to note that two of Japan's four ice dance teams have a non-Japanese partner.

Bryna OI of OI / MIZUTANI is American. She was 5th at 2009 New England Novice Regionals as a single. She switched to dance and was 6th at 2011 US Novice Nationals with partner Mark Jahnke. In the fall of 2011 she teamed with Taiyo Mizutani; they competed at 2012 Japanese Nationals and won in the absence of Reed/Reed, who were out with injury.

Marien De La Asuncion of HIRAI / DE LA ASUNCION previously competed for France with 3 different partners. He teamed up with Emi Hirai in 2011 after Emi's partnership with Taiyo Mizutani broke up (he teamed with Bryna Oi); they competed at 2012 Japanese Nationals and were second behind Oi / Mizutani.

You have to wonder why Japanese skaters pursue partnerships with non-Japanese partners (both male and female) knowing there is no hope of competing with those partners at the Olympics.

The two splits I can remember that worked out best were in pairs, Rodnina/Zaitsev and Kazakova/Dmitriev. When Rodnina's former partner Alexei Ulanov split with her under emotional and romantic circumstances, Rodnina was considered the treasure of the pair, and the Soviet federation hunted through the best they had for a partner. Rodnina/Zaitsev immediately took the top spot in the world and went on to win not one but two OGMs. (Rodnina already had a gold with Ulanov.) There are people who believe that Irina could have won a pairs gold medal skating alone; she was that good. But Zaitsev was clearly a wonderful partner for her, technically sound and emotionally cool under pressure.

In a later skating generation, after winning an OGM and then a silver with Natalia Mishkutenok, Artur Dmitriev split up with that partner, and he was paired with Oksana Kazakova. I'd say she wasn't quite up to his level, but she was good enough for him to win a second gold.

The only other really successful rearranged partnerships I can think of, meaning people who broke up and re-formed after winning some senior championships with the first partner, are Jenni Meno/Todd Sand (Sand broke up with the much younger Kuchiki after falling in love with Jenni) and Kyoko Ina/John Zimmerman after Ina broke up with Jason Dunjen. I'm sure there are others, though.

Today with the complexity of CoP rules, maybe it's not possible to do that sort of remixing anymore?

Edit: I made a correction to Dmitriev's medal history thanks to Victura's helpful troubleshooting.

In a later skating generation, after winning an OGM with Natalia Mishkutenok, Artur Dmitriev split up with that partner, and he was paired with Oksana Kazakova. I'd say she wasn't quite up to his level, but she was good enough for him to win an Olympic silver and then a second gold.

Just to clarify, Dmitriev won the gold in 1992 and silver in 1994 with Mishkutenok and only the second gold with Kazakova after Mishkutenok decided to retire. It's actually quite amazing what Kazakova did though, considering her only previous trip to senior Worlds before pairing up with Dmitriev was in 1994 where she and her previous partner placed 15th. Two seasons later, 5th, and another two seasons later, the Olympic gold.

Back on topic -- I too was very saddened to see this split and hope that Mervin and Narumi are both able to find partners that would take them back to the podium again. If even one of them is successful with a new partner, I'd be very pleased.